1. Field of the Invention
The present invention relates to a stable injectable composition containing prostaglandin E.sub.1. More specifically, the present invention relates to a stable injectable composition which is prepared by dissolving prostaglandin E.sub.1 in sodium citrate/citric acid buffer solution, filtering the resulting soultion under aseptic condition and then lyophilizing the filtrate, and wherein prostaglandin E.sub.1 is stably maintained even when the composition is stored for a long period.
2. Background Art
Prostaglandin E.sub.1 has been well known as a vasodilating agent and widely used in the clinical treatment of male sexual functional disorders such as erectile dysfunction, etc., and for induction and acceleration of labor pain and acceleration of delivery in the last stage of pregnancy. However, prostaglandin E.sub.1 has the disadvantage of being very unstable in solution and hard to store for a long period when it is prepared as injectable formulation. Furthermore, it is accompanied with serious pain when it is injected.
Therefore, the present inventors have extensively studied preparation of the stable injectable formulation of prostaglandin E.sub.1, which does not have the disadvantages as mentioned above, by preparing prostaglandin E.sub.1 into injectable formulations by means of various stabilizing agents. As a result, the present inventors have identified that when prostaglandin E.sub.1 is prepared in the form of an injectable formulation having a certain composition as mentioned below, a stable prostaglandin E.sub.1 injectable composition which is fit for the above purpose can be obtained.
Accordingly, the object of the present invention is to provide a stable injectable composition containing prostaglandin E.sub.1.
In addition, another object of the present invention is to provide a stable injectable composition prepared by dissolving prostaglandin E.sub.1 in sodium citrate/citric acid buffer solution, filtering the resulting solution under aseptic condition and then lyophilizing the filtrate.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed composition in a different manner, and such modifications are within the scope of the invention.